Over the weekend I took the time to finish one of my spreadsheets that enables us (Print4Pay Hotel members) to identify the cost per square foot for HP inkjet plotters. Let me tell you this was no easy task. Why in the world is there no information from HP that states how many mililiters of black ink is used to print one square foot for a CAD drawing? Every time I searched the HP web site for additional information about cost per page for Designjet plotters I was stymied by a notice that stated there was no information.I was able to find a few documents that related to color use, but nothing related to CAD drawings. Each HP plotter cartridge tells us how much ink is in the cartridge, but you'll never use all of the ink due to evaporation, ink head cleaning/purging and some residual ink left in the cartridge. For example one cartridge has 69ml (mililiters) of ink. Thus I was curious as to how much ink is a mililiter. A mililiter measure to be one thousandth of a liter. I know liters because that's because most of the soda bottles are now measured in liters, but how about a mililiter? Is that less than a shot glass, more than a tablespoon? I found this handy document that tells us 1ml is also equal to 1cc, 2.5 ml is equal to a half of teaspoon, 5ml is a teaspoon, and 30ml equal two tablespoons or 1 fluid ounce. Ok, I get it so the HP cartridge that hold 69 mililiters of ink is equal to a little more than 2 ounces. Since the cartridge resells for $69, the price per mililiter is $1.00.
As I stated the key was to

